Fluids produced from underground reservoirs are generally complex mixtures of materials such as aliphatic hydrocarbons, aromatic hydrocarbons, hetero-atomic molecules, anionic and cationic salts, acids, sands, silts and clays. The nature of these fluids, combined with the severe conditions of heat, pressure, and turbulence to which they are often subjected, are contributory factors to the formation and deposition of contaminants, such as scales, salts, paraffins, corrosion, asphaltenes and bacteria in underground reservoirs. In particular, such contaminants are deposited onto equipment and flow conduits used in hydrocarbon producing wells and non-hydrocarbon producing wells.
Corrosion of metallic surfaces during such treatments is a prominent issue, as evidenced by surface pitting, embrittlement and loss of metal. For instance, in such well stimulation techniques as pickling, acid washing, matrix acidizing and acid fracturing, the acidic nature of the treatment fluid causes the production or workover conduits in the well to encounter considerable acidic corrosion.
Further, aqueous fluids, such as those used in drilling and completion, have a high salt content which cause corrosion. Gases, such as carbon dioxide and hydrogen sulfide, also generate highly acidic environments to which metallic surfaces become exposed. For instance, corrosion effects from brine and hydrogen sulfide are seen in flow lines during the processing of gas streams. The presence of methanol, often added to such streams to prevent the formation of undesirable hydrates, further often increases the corrosion tendencies of metallic surfaces.
Further, naturally occurring and synthetic gases are often conditioned by treatment with absorbing acidic gases, carbon dioxide, hydrogen sulfide and hydrogen cyanide. Degradation of the absorbent and acidic components as well as the generation of by-products (from reaction of the acidic components with the absorbent) results in corrosion of metallic surfaces.
The deposition of scales and asphaltenes further presents problems as they reduce well productivity and shorten the lifetime of production equipment. In order to clean such deposits from wells and equipment it is necessary to stop the production which is both time-consuming and costly.
It is fairly common during such oilfield treatment processes to use treatment agents to inhibit or prevent the formation of such contaminants. Many conventional inhibitors, however, are becoming unacceptable for use in oilfield treatment processes due to environmental protections measures which have been undertaken. Alternative solutions to address the inhibition of formation of such contaminants have been sought.
It should be understood that the above-described discussion is provided for illustrative purposes only and is not intended to limit the scope or subject matter of the appended claims or those of any related patent application or patent. Thus, none of the appended claims or claims of any related application or patent should be limited by the above discussion or construed to address, include or exclude each or any of the above-cited features or disadvantages merely because of the mention thereof herein.